Arthroscopic system

ABSTRACT

An arthroscope having an elongated core with a square radial cross section.

This application is a continuation of U.S. application Ser. No.12/846,747 filed Jul. 29, 2010, now U.S. Pat. No. 9,375,139

FIELD OF THE INVENTIONS

The inventions described below relate to the field of arthroscopicsurgical instruments.

BACKGROUND OF THE INVENTIONS

Arthroscopic surgery involves using optical instruments, such as anarthroscope, to visualize an operating field inside or near a joint of apatient. The same instrument or other instruments may be used to performa surgical procedure in the operating field.

Known inflow and outflow arthroscope systems generally consist ofseveral elements, which include a flexible or rigid tube, a light thatilluminates the area the doctor wants to examine (where the light istypically outside of the body and delivered via an optical fibersystem), a lens system that transmits an image to the viewer from thearthroscope and another channel that allows the entry of medicalinstruments or manipulators. The lens systems typically usepre-manufactured square or rectangular shaped CCD chips. Traditionally,arthroscopes are circular so that the arthroscope does not have sharpedges that may cause trauma to tissue. When the chips are housed withinthe arthroscope, this results in a great amount of wasted space betweenthe square chips and the circular arthroscope that houses the chips.

SUMMARY

The devices and methods described below provide for an arthroscopehaving square or rectangular lateral cross section herein after referredto as a rectangle or rectangular. The arthroscope can be used in anarthroscopic system that also includes a scope sheath that is matched tothe dimensions of the arthroscope. The system includes a flow system,which sends fluid out of the end of the endoscope and brings debris andother fluid behind the field of view, thus allowing the surgeon to havea clear field of view while using the system.

This architecture allows the arthroscope to have a low profile thusmaking it less traumatic once introduced into anatomic spaces. Further,configuring the arthroscopic cross-section into the shape of thepre-manufactured CCD chip image configurations reduces costs associatedwith the manufacture of the scope.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an arthroscope having a sheath that encloses an elongatedcore that has a square radial cross section; the elongated core has animaging element on the distal end;

FIG. 2 illustrates a cross-sectional view along Line A-A of FIG. 1;

FIG. 3 illustrates an arthroscope having an optical cap;

FIG. 4 illustrates the features of the arthroscope pulled apart;

FIGS. 5a and 5b illustrate the elongated core of the arthroscope beforeit is folded into its final configuration;

FIG. 6 illustrates the elongated core of the arthroscope in its finalfolded configuration;

FIGS. 7a and 7b illustrate another elongated core before it is foldedinto its final configuration;

FIG. 8 illustrates another elongated core configuration;

FIG. 9 illustrates an elongated core with a square tube or solid mandrelfor additional rigidity;

FIG. 10 illustrates a method of performing arthroscopic surgery on apatient using an arthroscope containing an elongated core with a squareradial cross section;

FIG. 11 illustrates an arthroscope where the fluid management iscontained in a grommet-type cannula;

FIG. 12 illustrates an arthroscope that can be used without requiring auser to hold it, providing the user the opportunity to use thearthroscope hands free; and

FIG. 13 illustrates an arthroscope with a molded optical cap and 3-Dpositioning sensors.

DETAILED DESCRIPTION OF THE INVENTIONS

FIG. 1 shows an arthroscope 1 having a sheath that encloses an elongatedcore having a square radial cross section (see FIG. 2). Containedcentrally within a sheath 2, the elongated core has a square imagingchip 3 located at the distal end of the elongated core. The elongatedcore and the imaging chip together form the imaging core of thearthroscope. An atraumatic tip 4 at the distal end may also encase theimaging chip. The elongated core has a square radial cross section thatallows for the largest possible rectangular chip image package to beused in combination with the smallest possible round fluid sheathoutside diameter. This combination allows a clear pocket flow system,which sends fluid out of the end of the arthroscope and brings debrisand blood behind the operator's field of view. The system contains fluidoutflow 5 and fluid inflow channels 6. These channels are defined by thespace created between the elongated core and the circular sheathsurrounding it.

FIG. 2 illustrates a cross-sectional view along Line A-A of FIG. 1.Fluid enters the inflow channels 6 and flows axially into the joints.Fluid exits through the outflow channels 5 and comes behind the distalend of the arthroscopic sheath system and pulls blood and debris behindthe field of view of the user. The fluid flow is perpendicular to thesystem creating a pocket of clear fluid in front of the system where itis needed the most. An elongated core having square radial cross section7 is inserted into the sheath 2. The inner surface of the sheath 2 canhave an extruded profile for mating with the outer surface of theelongated core 7. The outer surface of the elongated core has tabs 8that mate tightly with the inner surface of the sheath in order toensure that the elongated core does not rotate within the sheath. Theforce of the elongated core pushing against the inner surface of thesheath forms a seal between the elongated core 7 and the inner surfaceof the sheath 2. As shown, fluid inflow 5 channels and fluid outflowchannels 6 are created between the outer sheath 2 and the elongated core7.

FIG. 3 illustrates an arthroscope 1 having an optical cap 9. Thearthroscope has an ergonomic handle 10 for user comfort. The handlecontains user control switches 11 that can provide focusing means forcontrolling the optical zoom of the system. At the distal end, thearthroscope also contains an electronics cable 12 and fluid inflow andoutflow tubing 13. Positioning of the electronics and fluid tubingeliminates clutter of conventional arthroscopes. The optical cap 9 ismade of a plastic material and is located at the distal end of thearthroscope. The optical cap 9 may serve as the objective lens if one isnot integrated into the imaging chip and associated package.Alternatively, the cap 9 may serve as a protective window, eitheroptically clear or with optical modifying properties such aspolarization or color filtering. The arthroscope also contains a fluiddrain and sensor window 14. A clear pocket flow of fluid flows axiallyto the system outflow from the distal end of the system. Drainage flowsthrough openings 15 in the sheath 2. Flow in this direction creates aclear fluid pocket in front of the arthroscope where it is required themost.

FIG. 4 illustrates the features of the arthroscope 1 pulled apart. Thedistal end of the elongated core has a multifunction connector 16 foruse with the video, pressure and temperature sensors. A round fluidsheath 2 is placed over the elongated core 7 and connected via a hub 17.The hub can be coupled to a multi-channel fluid manifold. The outsidediameter of the sheath closely matches the radial cross section of theelongated core to minimize the shape of the arthroscope. When engaged,the inner surface of the external sheath and the outer surface of theelongated core define a plurality of fluid channels extendinglongitudinally within the arthroscope. The fluid sheath can also have arectangular radial cross section closely matching the radial crosssection of the elongated core.

FIGS. 5a and 5b illustrate the elongated core 7 of the arthroscopebefore it is folded into its final configuration. FIG. 5a illustratesthe base of the elongated core. The elongated core is constructed onto aflat molded backing 18. The backing 18 contains folds to create hingepoints 19 that allow the backing to fold into the square configuration.The degree to which the folds are rotated allows the angle of theimaging chip to vary according to user preference. Pivot points 20 arecontained at each end of the backing for connection of the top andbottom faces of the elongated core. FIG. 5b illustrates the moldedbacking 18 with a flex circuit 21 laminated onto the molded hingebacking. The flex circuit 21 contains a pressure sensor 22 and atemperature sensor 23 as well as an imaging chip and its sensor moduleand associated lens 24. The lens can be made of plastic or other similarmaterial to assist in insulating the imaging chip and the insideelectronics from damage. In addition, an edge connector 25 is containedon one end of the molded backing for connection to desired system inputor power devices.

FIG. 6 illustrates the elongated core of the arthroscope in its finalfolded configuration. At the distal end the elongated core houses thedigital image CCD or CMOS chip and a sensor module 24 to enhance imagemagnification clarity and color. At the proximal end, the elongated corecontains a multifunction edge connector 25 for use with the temperature23 or pressure signal 22 connectors and to carry video signal. Thiselongated core is open on both sides. The elongated core 7 is formed byfolding over the backing 18 and connecting the top and bottom backingfaces at the pivot points 20. The elongated core shape is dictated bythe combination of the square chip and associated chip package that areof pre-determined sizes and commercially available. The elongated coremay contain one or multiple digital image chips within a singlearthroscope. Longitudinal movement of a first face of the backingrelative to a second face of the backing changes the angle of digitalimage CCD or CMOS chip to vary relative to the radial plane of theelongated core. The imaging end enables an indefinitely adjustable viewangle from 0 degrees to 90 degrees in a single scope. The arthroscopecan also accommodate for a 180 degree or retrograde view where thearthroscope has a flat top construction and a rotatable or living hingerectangular arthroscope architecture. The elongated core 7 can bereleasably mounted to a base such that the core can be sterilized andreused for a number of surgical procedures.

FIGS. 7a and 7b illustrate another elongated core 7 before it is foldedinto its final configuration. FIG. 7a illustrates the backing 18 of theelongated core. The elongated core is constructed onto the moldedbacking 18 that contains protrusions 26 spaced apart at a predetermineddistance. The protrusions on each face are matched to mate when in afolded configuration. When folded, the protrusions construct a solidelongated core. The elongated core has a square radial cross sectionwith a proximal end, a distal end spaced from the proximal end forinsertion into a body, a top surface, a bottom surface. The elongatedcore also has two opposite side surfaces adjacent to the top and bottomsurfaces. At least one of the surfaces may contain a metal strip bondedto the top of the surface. The metal strip may be a spring steel ornickel-titanium alloy with a preformed radius of curvature. The metalalloy may alternatively be a malleable metal such as aluminum or may bea nickel-titanium (nitinol) alloy with a shape memory feature. The metalstrip allows the elongated core to reliably bend in one plane ofcurvature. Where the memory backing is spring-steel or nitinol, it maybend to a shape if malleable, or may be made steerable with a nitinolshape-memory component.

The elongated core contains planes that provide structural rigidity tothe elongated core. The protrusions can have a locking taperconstruction. In addition, the protrusions can be joined with anadhesive or can be welded together thermally or with ultrasonic weldingtechniques. The elongated core also contains an imaging device chipfitted at the distal end of the elongated core where the imaging surfaceis arranged in a viewing direction of the elongated core. In addition,the elongated core has an illumination source at the proximal end forilluminating a surgical site at which the arthroscopic sheath system isdirected. The core backing 18 contains folds that create hinge points 19to allow the backing to fold into a rectangle. Pivot points 20 arecontained at each end of the backing for connection of the top andbottom faces of the elongated core. FIG. 7b illustrates the moldedbacking 18 with a flex circuit 21 laminated onto the molded hingebacking. The flex circuit 21 contains the pressure and temperaturesensors 22, 23 as well as the imaging chip and its associated LEDpackage 24. In addition, the edge connector 25 is contained on one endof the molded backing.

FIG. 8 illustrates another elongated core configuration. The distal endof the elongated core 7 houses the digital image CCD or CMOS chip andsensor module 24. The distal end can also contain imaging modalitiesother then visible light devices such as ultrasonic transducers andoptical coherence tomography (OCT) imagers in addition to the CCD andCMOS video imagers. At the proximal end, the elongated core contains amultifunction edge connector 25 for use with temperature or pressuresignal connectors. The intermediate body of the elongated core is in theform of vertebrated or specifically profiled sections 27 located at apredetermined distance from each other to enhance steerability of theelongated core when inserted into the patient. The elongated core istransversely slotted along its entire length to form this configuration.

FIG. 9 illustrates an elongated core with a square tube or solid mandrelfor additional rigidity. The rectangular mandrel may serve as anillumination conduit. The assembly has an optically transparent lightpipe center core 28 that allows light to pass through. Illuminationlight emanating from a light source apparatus passes through thetransparent core, is converged by a lens, and falls on the opposing endsurface of the illumination conduit. The illumination light istransmitted to the arthroscope over the illumination conduit, passesthrough the arthroscope, and is emitted forward through the distal endof the arthroscope. Thus, an object in the patient's body cavity isilluminated. An image represented by the light reflected from theilluminated object is formed by the arthroscope. A resultant objectimage is projected by the imaging means through the scope. The opticallytransmitting center core is a rectangular shaped housing or mandrel madeof a molded plastic material that can transmit light from the proximalend and out of the distal end. The center core is made of any clearmolded polycarbonate or acrylic plastic material that can be easilymolded. The molded plastic mandrel has an LED illumination module 29 atthe proximal end and the assembly circuitry 30 is wrapped around thecenter core. The edge connector 25 is also contained at the proximal endof the assembly. The chip imaging module 24 is contained at the distalend of the assembly. In addition, the distal end of the assembly servesas the transmitting end of the light pipe created by the center core.The advantage to the assembly is that it has a small cross-section, butis very robust and easy to use. The assembly is inexpensive tomanufacture and provides adequate illumination to the arthroscope.

FIG. 10 shows a method of performing arthroscopic surgery on a patient31 using an arthroscope in an atraumatic sheath 2. Various anatomicallandmarks in the patient's knee 32 are shown for reference, includingthe femur 33, patella 34, posterior cruciate ligament 35, anteriorcruciate ligament 36, meniscus 37, tibia 38 and fibula 39. Duringsurgery, the surgeon introduces the arthroscope into the knee via afirst incision 40 in order to visualize the surgical field. A trimminginstrument 41 is introduced through a second incision 42 to remove ortrim tissue that the surgeon determines should be removed or trimmed.

FIG. 11 illustrates an arthroscope where the fluid management iscontained in a grommet-type cannula. The arthroscope has an angle setcollar 45 and an elastomeric portal cannula 46. When the collar is notpressed to the elastomeric cannula, the scope set perpendicular to theportal. When the sleeve is pushed forward, the scope is angled in theportal. Where the collar is rotated, the arthroscope can be directed toan area of interest radially within the surgical space. The ability totranslate, rotate and hold the scope can be accomplished with a ballgimbal or other similar means. This frees the hands of the surgeon touse their instruments rather than have to hold the arthroscope inposition.

FIG. 12 illustrates an arthroscope that can be used without requiring auser to hold it, providing the user the opportunity to use thearthroscope hands free. The arthroscope has an angle set collar 45, anelastomeric portal cannula 46 and a grommet cannula 47 to allow forfluid inflow and outflow through the grommet cannula. The fluid and gasmanagement connections are removed from the arthroscope. The arthroscopealso contains a wireless scope 48 that accommodates for multiple scopesto communicate on a network. This allows the arthroscope to be wirelessand untethered by either wires or fluid tubes and instead to be aimedand held on a point of interest. This provides the advantage that thesurgeon can use both hands while operating on a patient and can beuseful in telemedicine applications. The arthroscope is wireless and canbe networked together with a ZigBee, MESH or Bluetooth wireless network.

FIG. 13 illustrates an arthroscope with a molded optical cap and 3-Dpositioning sensors. Spatial positioning and tracking sensors 49 can beattached to 3 of the 4 orthogonal sides of the arthroscope. Thesesensors can read optically, ultrasonically, or with an RFID system. Thepositioning and tracking system allows the arthroscope to be positionedaccurately in space and can be used to guide surgical instruments andprovide accurately guided cutting of tissue. In addition, due to thearthroscope's flat surface, a linear encoder 50 can be added to thearthroscope using circuit printing lithography techniques. This can beused to accurately gauge the depth of penetration of the scope into thesurgical field. A reader 51 for the linear encoder is disposed within anaccess cannula. The data from the 3-D positioning and tracking means 49and linear encoder 50 may be transmitted for display and processingeither wired, or wirelessly. The 3-D and linear positioning encoders maybe on two or more arthroscopes and can communicate and network togetherwith a ZigBEE MESH network, Bluetooth 802.11 or other wireless protocol.The 3-D positioning and tracking can be useful for robotic surgery,virtual template aided surgery, augmented reality surgical visualizationand high-risk surgery, or implant surgery where geometrically accuratecutting is essential to the proper alignment of a device such as anorthopedic implant. The system also has an optical cap 52 to protect theimaging chip from fluids. The cap is molded of acrylic, polycarbonate,or other appropriate optically clear plastic. The cap may be molded witha spherical lens, an aspheric lens, or a split stereoscopic lens thatprojects a binocular image on to the imaging chip. The central squarerod may have a structural center core (e.g. stainless steel ortitanium), to give the scope strength, and the perimeter of the rod maybe clad with an optically clear light pipe of a light-transmittingplastic. The rod is illuminated at the proximal end with an LED lightsource or a fiber optic cable, and the light is transmitted through apipe light, through the optical cap 52 out the distal end to illuminatethe surgical field. On the perimeter, the optical cap may have acondensing lens feature, or a light diffusion means to tailor theillumination to the clinical needs of the surgeon. The system may beused with a fluid management sheath and means previously disclosed. Alsothe ability to build 100% polymer and non-ferrous arthroscope allows itsuse in radiology guided applications where the materials must benon-magnetic, such as under MRI applications.

In use, a surgeon inserts the elongated core into the sheath ofcorresponding size. The elongated core creates the most space efficientconfiguration in that the insertion of the elongated core into thesmallest complimentary circular shaped sheath eliminates wasted space.In addition, the arthroscope allows for an efficient clear pocket viewflow of fluid inflow and outflow to create a clear field of view for thesurgeon. Also, the arthroscope can be used as a retractor once insertedin the patient.

The arthroscope architecture allows the largest possible elongated coreto be used in the smallest scope sheath. The elongated core dimensionsare matched to the scope sheath to accommodate for a low profile system.Further, the arthroscope allows for a flat rectangular scope with apanoramic view, as well as 3-D viewing where two chips are placedside-by-side. In addition, multiple arthroscopes can be used at the sametime in a single application system. Two or more arthroscopes can beaimed at a particular area of interest and the user can switch betweenthe arthroscopic cameras with a selector device such as a footswitch.This frees up the user's hands to focus on other surgical instrumentssuch as an arthroscopic shaver or stitcher without requiring use of hishands to hold the camera in place. The multiple arthroscopeconfiguration can be held in place by a portal plug device. The plug canhave an angled foot and be rotated to place the arthroscope at thedesired angle. A plug can anchor the surgical portal as well as providea means for sealing the portal to prevent leakage of fluid or gas. Theplug can have a square inner lumen to seal against a square arthroscopethat does not have an outer round sheath. The two or more cameras can beswitched back and forth to cover multiple locations from a centralconsole. The cameras can be of different focal lengths or have imagingcapabilities such as narrow-light band imaging, near infra-red, opticalcoherence tomography miniature radiology device or other non visiblelight imaging modalities.

The word arthroscope used herein includes a family of instruments,including endoscopes, laparoscopes and other scopes. The scopes may userod optics, fiber optics, distally mounted CCD chips, or other opticalsystems. Thus, while the preferred embodiments of the devices andmethods have been described in reference to the environment in whichthey were developed, they are merely illustrative of the principles ofthe inventions. Other embodiments and configurations may be devisedwithout departing from the spirit of the inventions and the scope of theappended claims.

We claim:
 1. A method of performing arthroscopic surgery, said methodcomprising the steps of: providing an arthroscope, said arthroscopecomprising: a molded elongated core having an inner and outer surfaceand a square radial cross section and having a proximal end, a distalend spaced from the proximal end for insertion into a body, a topsurface with at least one hinge point, and a bottom surface with atleast one hinge point, the top and bottom surfaces spaced apart at apredetermined distance ; and an imaging chip fitted at the distal end ofthe elongated core having an imaging surface arranged in a viewingdirection of the arthroscope; placing the arthroscope inside of a sheathhaving an outer diameter and an inner diameter, the inner diameterhaving an extruded profile and having an inner surface and an outersurface, the extruded profile of the inner diameter of the sheathadapted to mate with the protrusions on the top and bottom surface ofthe elongated core, the inner surface of the sheath defining a pluralityof fluid channels longitudinally extending within the arthroscope;adjusting the top surface of the elongated core via longitudinalmovement of the top surface of the elongated core relative to the bottomsurface of the elongated core in order to change an angle of the imagingchip relative to a radial plane of the elongated core; and performing anarthroscopic surgical procedure.
 2. The method of claim 1 furthercomprising a fluid manifold comprising a plurality of fluid pathwayscommunicating with an inflow channel that extends longitudinally withinthe arthroscope and an outflow that extends longitudinally within thearthroscope whereby the fluid manifold is operably connected to theexternal sheath.
 3. The method of claim 2 further comprising introducingfluid via a body cavity through the inflow channel and then exiting thefluid from the body cavity through the outflow channel disposed proximalof the inflow channel, wherein an opening to the outflow channel isformed within an outer wall of the sheath such that fluid flowsperpendicular to a longitudinal axis of the arthroscope to enter theoutflow channel from the opening.
 4. The method of claim 1 furthercomprising providing an illumination source at the proximal end of thearthroscope for illuminating a surgical site at which the arthroscope isdirected.
 5. The method of claim 1 wherein the arthroscope furthercomprising two opposite side surfaces adjacent to the top and bottomsurfaces.